Improved direct measurement of leptonic coupling asymmetries with polarized Z bosons

We present final measurements of the Z boson-lepton coupling asymmetry parameters A(e), A(mu), and A(tau) with the complete sample of polarized Z bosons collected by the SLD detector at the SLAC Linear Collider. From the left-right production and decay polar angle asymmetries in leptonic Z decays we measure A(e) = 0.1544+/-0.0060, A(mu) = 0.142+/-0.015, and A(tau) = 0.136+/-0.015. Combined with our left-right asymmetry measured from hadronic decays, we find A(e) = 0.1516+/-0.0021. Assuming lepton universality, we obtain a combined effective weak mixing angle of sin (2)theta(eff)(W) = 0.230 98+/-0.000 26.

First symmetry tests in polarized Z0 decays to bbg

We have made the first direct symmetry tests in the decays of polarized Z0 bosons into fully identified bbg states, collected in the SLD experiment at SLAC. We searched for evidence of parity violation at the bbg vertex by studying the asymmetries in the b-quark polar- and azimuthal-angle distributions, and for evidence of T-odd, CP-even or CP-odd, final-state interactions by measuring angular correlations between the three-jet plane and the Z0 polarization. We found results consistent with standard model expectations and set 95% C. limits on anomalous contributions.

Schwannomas of the upper extremity

This study presented the clinical characteristics, MRI features and postoperative results of 20 schwannomas in the arms of 13 patients. Twelve tumours had a positive Tinel's sign, one caused weakness of the wrist and another in Guyon's canal caused hypothenar muscle atrophy. Of the nine cases which underwent magnetic resonance imaging preoperatively, six were correctly diagnosed as schwannomas. All masses were excised using microsurgical techniques and two transient neurological complications occurred.

Haloperidol-induced neuronal apoptosis: role of p38 and c-Jun-NH(2)-terminal protein kinase

We examined patterns and mechanisms of cell death induced by haloperidol. Cortical cell cultures exposed to 10-100 microM: haloperidol for 24 h underwent neuronal death without injuring glia. The degenerating neurons showed hallmarks of apoptosis, featuring cell body shrinkage, nuclear chromatin condensation and aggregation, nuclear membrane disintegration with intact plasma membrane, and prominent internucleosomal DNA fragmentation. Neither glutamate antagonists nor antioxidants prevented the haloperidol-induced neuronal apoptosis. The c-Jun-NH(2)-terminal protein kinase and p38 mitogen-activated protein kinase were activated within 1 h and were sustained over the next 3 h following exposure of cortical neurons to 30 microM haloperidol. Haloperidol-induced neuronal apoptosis was partially attenuated by 10-30 microM PD169316, a selective inhibitor of p38 mitogen-activated protein kinase. Inclusion of 1 microg/ml cycloheximide, a protein synthesis inhibitor, or 100 ng/ml insulin prevented activation of both kinases and subsequent neuronal death. The present study demonstrates that cortical neurons exposed to haloperidol undergo apoptosis depending on activation of p38 mitogen-activated protein kinase and c-Jun-NH(2)-terminal protein kinase sensitive to cycloheximide and insulin.

Measurement of radiation absorbed dose in endovascular Ho-166 brachytherapy using a balloon angio-catheter

The purpose of this study was to estimate the absorbed dose distribution of Ho-166 endovascular beta irradiation using an angio-catheter. The liquid form of Ho-166 was produced at the Korea Atomic Energy Research Institute (KAERI) by an (n,gamma) reaction. Ho-166 has a half-life of 26.8 h and emits a high-energy beta particle with a maximum energy of 1.85 MeV. GafChromic film was used for the estimation of the absorbed dose of beta particles. A Co-60 teletherapy source and a 6 MV photon beam from a linear accelerator were used to generate dose-optical density calibration curves. The exposed films were read using a videodensitometer. With a modified micrometer, the film was positioned accurately on the surface of the balloon in water. The balloon was filled with Ho-166 solution to a pressure of 4 atm. Several film exposures were made with varying irradiation times and activities. The radiation absorbed dose rates were 1.02, 0.51 and 0.35 Gy x min(-1) x GBq(-1) x ml(-1) at the balloon surface, 0.5 and 1 mm from the balloon surface, respectively. The absorbed dose distribution revealed that Ho-166 is a good source for endovascular irradiation as the beta range is very short, avoiding unnecessary irradiation of normal tissue. A clinically applicable irradiation and duration of exposure were achievable utilizing our system.

Effect of transcatheter endovascular radiation with holmium-166 on neointimal formation after balloon injury in porcine coronary artery

BACKGROUND

Neointimal formation in response to arterial injury is a major contributing element in restenosis after coronary balloon angioplasty and stenting. Endovascular irradiation has been reported to be effective in reducing restenosis. The purpose of this study was to investigate the effect of beta-emitting holmium-166 for the inhibition of neointimal formation in porcine coronary artery.

METHODS AND RESULTS

A total of 34 pigs weighing 25 to 30 kg underwent oversized balloon injury (balloon/artery ratio, 1.3:1.4) at the proximal portion of the left anterior descending and circumflex arteries. One artery was randomly assigned to receive radiation after injury. Ho-166 was left in the balloon within the delivery catheter for a period sufficient to deliver 9 Gy and 18 Gy to a depth of 1 mm from the surface of the balloon. Four weeks later, pigs were sacrificed and hearts were perfusion-fixed, followed by histopathologic analysis and planimetry for measurement of maximal intimal thickness, intimal area, and fracture length. The coronary segment of the pigs in the control group had neointimal area of 1.18+/-0.55 mm2; the pigs in the 9-Gy group had neointimal area of 0.68+/-0.40 mm2 (P<.05 vs. control); and the pigs in the 18-Gy group had neointimal area of 0.29+/-0.12 mm2 (P<.01 vs. control). The maximal intimal thickness in the 18-Gy group (0.14+/-0.11 mm) was significantly reduced compared with the maximal intimal thickness in the control group (0.48+/-0.13 mm) (P<.01).

CONCLUSIONS

Intracoronary radiation with liquid Ho-166 contained in a perfusion balloon catheter is feasible and effective in reducing neointimal formation after coronary overstretch injury in pigs. Therefore intracoronary irradiation on the injured segment may further reduce restenosis after balloon injury.

Transcriptional induction of Nur77 by indomethacin that results in apoptosis of colon cancer cells

Non-steroidal anti-inflammatory drugs (NSAIDs) have cancer preventive and tumor regressive effects in the human colon, perhaps due to their capability to induce apoptosis of the colon cancer cells. Here, we report that indomethacin induced the expression of Nur77 which has been implicated in activation-induced apoptosis of T-lymphocytes, in a colon cancer cell line, HCT-15. The transcript- and protein-level, the transcriptional activity of Nur77 promoter, and the DNA binding of Nur77 were significantly induced following indomethacin treatment. Among the two potential trans-acting factors that activate Nur77-promoter, indomethacin induced DNA binding and reporter gene activity of AP-1, but not that of related serum response factor (RSRF), suggesting that the transcriptional induction of Nur77 may be mediated through activation of AP-I. Further, we showed that all trans-RA repressed the induction of Nur77 as well as the apoptosis-induced by indomethacin, providing evidence that transcriptional induction of Nur77 may be an important mechanism by which indomethacin induces apoptosis in colon cancer cells.

Retinoic acid and its receptors repress the expression and transactivation functions of Nur77: a possible mechanism for the inhibition of apoptosis by retinoic acid

Nur77 (NGFI-B) is an orphan nuclear receptor that has been implicated in activation-induced T-cell apoptosis. Retinoids, potent immune modulators, were shown to inhibit the activation-induced apoptosis of immature thymocytes and T-cell hybridomas. To illustrate the mechanism of the inhibition, we examined the effects of retinoic acid (RA) on the expression and transactivation functions of Nur77 in the human peripheral blood mononuclear cells and the human T-cell leukemia, Jurkat. All-trans-RA remarkably repressed the DNA binding and transcriptional induction of Nur77. Among the two potential trans-acting factors that activate Nur77 gene promoter, i.e., AP-1 and related serum response factor (RSRF), all-trans-RA repressed DNA binding and reporter gene activity of AP-1 but not that of RSRF, suggesting that the inhibition may be mediated through AP-1. We also demonstrated a posttranscriptional regulation of Nur77 function by retinoid receptors by showing that transactivation activity of Nur77 was significantly inhibited by cotransfection of RARalpha or RXRalpha. Nur77 bound RARalpha or RXRalpha in both yeast and mammalian two-hybrid tests, suggesting that direct protein-protein interaction between these receptors may mediate the inhibition. Taken all together, we demonstrated that RA repressed Nur77 function through multiple mechanisms that may provide the basis for RA inhibition on the apoptosis of activated T-lymphocytes.

Activation of NF-kappaB determines the sensitivity of human colon cancer cells to TNFalpha-induced apoptosis

Tumor necrosis factor alpha (TNFalpha) generates a potent cytotoxic effect, however many cancer cells are resistant to TNFalpha-mediated killing and the cause of the differential sensitivity remains to be elucidated. In this study, we demonstrated that TNFalpha induced cell death in four different human colon cancer cell lines. The degree of cytotoxic effect was different in each cell line, in that HCT-15 was relatively sensitive, while DLD-1, HT-29 and WiDr were relatively resistant. TNFalpha induced apoptotic changes such as morphological changes, DNA fragmentation and activation of caspase-3 in HCT-15, but to a lesser degree in the others. Transcriptional expression of TNFR1(p55), as well as that of FLICE, Fas, FADD, DR3, FAF, TRADD, and RIP was similar in these cell lines, indicating that the susceptibility to TNFalpha-induced apoptosis may not be determined by the constitutive expression level of these factors. Interestingly, the cytotoxic effect of TNFalpha was well correlated with the DNA binding activity of NF-kappaB in the colon cancer cell lines. Further, the overexpression of a non-phosphorylated mutant form of IkappaBalpha enhanced the cytotoxicity of TNFalpha in the resistant cell line, DLD-1, indicating that NF-kappaB activity may determine the sensitivity of colon cancer cells to TNFalpha-induced apoptosis. Thus, our results indicate that modulation of NF-kappaB activity may provide a useful tool to sensitize colon cancer cells to TNFalpha treatment.

Prediction of sound transmission loss through multilayered panels by using Gaussian distribution of directional incident energy

In this study, a new prediction method is suggested for sound transmission loss (STL) of multilayered panels of infinite extent. Conventional methods such as random or field incidence approach often given significant discrepancies in predicting STL of multilayered panels when compared with the experiments. In this paper, appropriate directional distributions of incident energy to predict the STL of multilayered panels are proposed. In order to find a weighting function to represent the directional distribution of incident energy on the wall in a reverberation chamber, numerical simulations by using a ray-tracing technique are carried out. Simulation results reveal that the directional distribution can be approximately expressed by the Gaussian distribution function in terms of the angle of incidence. The Gaussian function is applied to predict the STL of various multilayered panel configurations as well as single panels. The compared results between the measurement and the prediction show good agreements, which validate the proposed Gaussian function approach.

Ideal concentration of growth factors in rabbit's flexor tendon culture

Growth factors have the ability to stimulate matrix synthesis and cell proliferation in rabbit flexor tendon. Maximal stimulation effects of growth factors have a wide variation. It depends upon the different anatomic sites of the tendon segment, the kinds of growth factor, the concentration of growth factors, and the time sequence. Since proliferation was an early component of intrinsic tendon healing, we investigated the short-term dose response to four different growth factors on in vitro rabbit's tendon culture. We evaluated the effects according to the various concentrations of recombinant human insulin-like growth factor 1 (IGF), recombinant human epidermal growth factor (EGF), fibroblast growth factor (FGF), and recombinant human platelet-derived growth factor-BB (PDGF). Fetal calf serum was the most potent stimulator of cell proliferation and protein synthesis in in vitro rabbit's tendon culture. Matrix synthesis and cell proliferation were stimulated dose-dependently by IGF between the doses of 50 and 150 ng/ml. The maximum mitogenic effect of EGF was observed at the concentration of 100 ng/ml (1.3 times more than the media-only control culture). The rabbit's tendon responded significantly dose-dependently to PDGF, whereas there was no significant response to FGF.

Mutations in the 1A rod domain segment of the keratin 9 gene in epidermolytic palmoplantar keratoderma

Palmoplantar keratodermas (PPK) constitute a heterogeneous group of diseases marked by the thickening of palms and soles of affected individuals. They are divided into autosomal dominant and autosomal recessive groups by the mode of transmission. The autosomal dominantly transmitted group is further divided into epidermolytic (EPPK, Voerner) and non-epidermolytic (NEPPK, Unna-Thost) types according to the histopathologic findings. Recent development of molecular approaches has confirmed that EPPK and NEPPK are caused by the mutations in keratin 9 and 1 genes, respectively. We have studied three families of EPPK to find the mutation in the keratin 9 gene. DNA sequence analyses revealed single base changes in sequences encoding the highly conserved 1A rod domain segment of the keratin 9 gene in two of the three families. These mutations caused Arg (CGG) to Glu (CAG; R162Q) and Arg (CGG) to Try (TGG; R162W) substitutions. The same arginine position has been mutated in the keratin 10 gene in epidermolytic hyperkeratosis, the keratin 14 gene in epidermolysis bullosa simplex, and the keratin 9 gene in hereditary EPPK in Western patients. In this study we show that unrelated Korean patients have similar mutations.

A glutamate to lysine mutation at the end of 2B rod domain of keratin 2e gene in ichthyosis bullosa of Siemens

Ichthyosis bullosa of Siemens is a rare autosomal dominant skin disorder whose clinical findings are quite similar to those of epidermolytic hyperkeratosis. The differences between those two diseases include absence of erythroderma and different distributions in the skin in ichthyosis bullosa of Siemens. Recent studies have confirmed that ichthyosis bullosa of Siemens is caused by the mutation in the keratin 2e (K2e) gene, which is expressed in the upper spinous and granular layers. We have identified a sporadic case of ichthyosis bullosa of Siemens; based on diagnosis by histopathological findings, the K2e gene of the patient was analysed. Direct sequencing of PCR products revealed a single base change in sequences encoding the highly conserved end of the 2B rod domain segment of the K2e gene. This mutation results in substitution of the codon for glutamic acid by a codon for lysine in position 493 in K2e (E493K). Mutations of the K2e gene involving five different residue positions (Q187P, T485P, L490P, E493D, E493K and E494K) are known to cause ichthyosis bullosa of Siemens. Of these sites, E493, which is conserved in type I and type II keratin genes, is the most frequently altered amino acid in the K2e gene. These data together suggest that this codon constitutes a hot spot for mutations in the K2e gene.

Anticardiolipin and anti-beta2-glycoprotein I antibodies in Behcet's disease

To investigate prevalence of anticardiolipin antibodies (aCL) in patients with Behcet's disease (BD) and to determine whether they are related to anti-beta2-glycoprotein I antibodies (aGPI), we measured aCL and aGPI in 47 patients of BD and 14 patients of systemic lupus erythematosus (SLE). The levels of aCL and aGPI were determined by conventional enzyme immunoassay for both IgG and IgM classes. Twelve (25.5%) patients with BD were positive for IgG or IgM aCL and no patient was positive for aGPI. Eleven (78.6%) patients with SLE were also positive for aCL and among them, 8 (72.7%) patients were positive for aGPI. Positive IgG aCL patients with BD showed lower level of IgG aCL than those with SLE (15.7+/-7.3 vs 34.1+/-16.0 GPL, p<0.05). There was no relation between the presence of aCL in BD and either dinical activity or clinical features. In the patients with BD, aCL are found but it would not be associated with aGPI as they are in patients with SLE. In patients with BD, aCL seem to be authentic aCL unlike those in patients with SLE and may not be related with vascular complications in BD.

Fracture of the ipsilateral neck of the femur in shaft nailing. The role of CT in diagnosis

We report retrospective and prospective studies to identify the causes of fracture of the femoral neck associated with femoral shaft nailing on the same side. Of a total of 14 neck fractures in a series of 152 shaft nailings, eight were not visible on the initial pelvic radiographs. We used CT scans before and after operation, and fluoroscopy during the procedure in our prospective series, and reviewed abdominal CT scans retrospectively with the window set to bone level. Six of the eight undisplaced fractures were shown to have been present before operation, but two were iatrogenic. We recommend the preoperative use of CT scans of the femoral neck in high-risk patients such as those with associated fractures of the acetabulum, the distal femur or the patella. Early diagnosis will allow better general management and early fixation of the neck fracture.

Modified step-cut osteotomy of the humerus

Corrective osteotomy of the distal humerus for a posttraumatic cubitus varus was performed in 31 patients using a modified step-cut osteotomy. The average patient age was 14.3 years. Complete bony union was obtained between the 8th and 16th weeks. Twenty-one patients achieved excellent results, 7 achieved good results, and 3 achieved poor results on the basis of Oppenheim's criteria. Although the results for 28 patients (90.3%) were classified as excellent or good, 6 patients (19.3%) were subjectively disappointed due to bulging of the lateral condyle. We achieved an overall improvement in mechanical stability and established an easier technique in corrective osteotomy. However, this approach may not be appropriate if the correction angle desired is greater than 30 degrees.

Physiologically based pharmacokinetic models of 2',3'-dideoxyinosine

PURPOSE

The goal of this study was to develop physiologically based pharmacokinetic (PBPK) models for 2',3'-dideoxyinosine (ddI) in rats when the drug was administered alone (ddI model) and with pentamidine (ddI + pentamidine model), and to use these models to evaluate the effect of our previously reported pentamidine-ddI interaction on tissue ddI exposure in humans.

METHODS

The PBPK models consisted of pharmacologically relevant tissues (blood, brain, gut, spleen, pancreas, liver, kidney, lymph nodes, muscle) and used the assumptions of perfusion-rate limited tissue distribution and linear tissue binding of ddI. The required physiologic model parameters were obtained from the literature, whereas the pharmacokinetic parameters and the tissue-to-plasma partition coefficients were calculated using plasma and tissue data.

RESULTS

The ddI model in rats yielded model-predicted concentration-time profiles that were in close agreement with the experimentally determined profiles after an intravenous ddI dose (5% deviation in plasma and 20% deviation in tissues). The ddI + pentamidine model incorporated the pentamidine-induced increases of ddI partition in pancreas and muscle. The two PBPK models were scaled-up to humans using human physiologic and pharmacokinetic parameters. A comparison of the model-predicted plasma concentration-time profiles with the observed profiles in AIDS patients who often received ddI with pentamidine showed that the ddI model underestimated the terminal half-life (t1/2, beta) by 39% whereas the ddI + pentamidine model yielded identical t1/2, beta and area-under-the-curve as the observed values (< 1% deviation). Simulations of ddI concentration-time profiles in human tissues using the two models showed that pancreas and lymph nodes received about 2- to 30-fold higher ddI concentration than spleen and brain, and that coadministration of pentamidine increased the AUC of ddI in the pancreas by 20%.

CONCLUSIONS

Data of the present study indicate that the plasma ddI concentration-time profile in patients were better described by the ddI + pentamidine model than by the ddI model, suggesting that the pentamidine-induced changes in tissue distribution of ddI observed in rats may also occur in humans.

Integration of surgery in multimodality therapy for esophageal cancer

BACKGROUND

While adding chemotherapy to radiation for the treatment of esophageal cancers has been shown to be beneficial, surgery usually follows treatment or is omitted. In either case, regional control remains problematic. The purpose of this study was to test the feasibility of using chemotherapy and radiation following surgery in the treatment of of esophageal cancer and to assess the impact of this approach on regional control and survival.

PATIENTS AND METHODS

Twenty-five patients with esophageal cancer were treated in a phase I pilot protocol consisting of initial esophagectomy with gastroesophagostomy and subsequent combined chemotherapy and radiation. Chemotherapy consisted of cisplatin given on day 1 and 5-fluorouracil (FU) on days 1-5 by continuous infusion. Radiation therapy was administered in varying fractionation schedules of once or twice daily concomitantly with the chemotherapy. Treatment was repeated every other week for two to four cycles. Median follow-up was 42 months.

RESULTS

Acute toxicities (mucositis and cytopenias) were common but not worse than grade 3. Higher doses of 50 Gy with 2 Gy b.i.d. hyperfractionation caused late complications in four of 10 patients, (two lethal). Control of local disease for all patients was excellent with only two known and two possible local recurrences (16%) but distant metastases were common (46%). Disease-free survival was 58 and 30% at 1 and 2 years, respectively. Survival was 58 and 32% at 1 and 2 years, respectively (median survival, 19 months).

CONCLUSION

The local control rate and survival were better than those in our historical experience with cisplatin and 5-FU chemotherapy and radiation given prior to surgery. A dose-fractionation schedule of < 2 Gy up to a total of 50 Gy b.i.d. is recommended to avoid late adverse effects. The role of surgery will be defined by randomized studies. Better systemic therapy is needed to impact on systemic failure.

Biomechanical changes of cadaveric finger flexion: the effect of wrist position and of the transverse carpal ligament and palmar and forearm fasciae

This study was designed to investigate whether the position of the wrist or sectioning of the transverse carpal ligament (TCL), as well as the palmar fascia and forearm fascia, modifies the biomechanical behavior of the finger flexion, as defined by changes of excursion, load (force), and work of the flexor tendons. The parameters were measured in fresh-frozen cadaver hands with the wrist in 30 degree extension, neutral, and 30 degree flexion, before and after division of the TCL. Having the wrist in extension improved excursion efficiency, whereas flexing the wrist produced the opposite effect, with a 16% decrease in excursion efficiency after division of the TCL. Change in excursion efficiency between the intact and cut TCL was 8% in the flexed position, 5% in the neutral position, and 0.3% in the extended position. Change in load efficiency between intact and cut TCL was 11% in the flexed position, 6% in the neutral position, and 0% in the extended position. Change in the work efficiency between intact and cut TCL groups was noted most with the wrist in the flexed position (13%), compared to a small change (3%) in neutral wrist position and no change in wrist extension. A significant decrease in the excursion efficiency of the flexor tendons was demonstrated when the wrist was in the flexed position. Any increase in the excursion of the flexor tendons could clinically result in decreased grip strength when the wrist is flexed. Furthermore, the effects of TCL division were not significant when wrist position was in extension.

Effects of protein kinase inhibitors on the stimulated neutrophil responses by degraded immunoglobulin G

Effects of protein kinase C inhibitors, staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine dihydrochloride and protein tyrosine kinase inhibitors, genistein, tyrphostin and 2,5-dimethylcinnamate on the neutrophil responses stimulated by immunoglobulin G (IgG), complement C5a or platelet-activating factor were studied. After receptor binding, the role of protein kinase C and protein tyrosine kinase in the stimulation of neutrophil responses, superoxide production and lysosomal enzyme release in degraded IgG-activated neutrophils may be similar to chemoattractant-stimulated cells. In contrast to complement C5a or platelet-activating factor, protein tyrosine kinase appears to play an important role in the regulation of intracellular Ca2+ mobilization in neutrophils activated by degraded IgG rather than by protein kinase C.

Pharmacokinetic interaction between intravenous 2',3'-dideoxyinosine and pentamidine in rats

PURPOSE

This study examined the pharmacokinetic interaction between 2',3'-dideoxyinosine (ddI) and pentamidine.

BACKGROUND

ddI and pentamidine are often coadministered to patients with acquired immunodeficiency syndrome, and are both associated with pancreatic toxicity. Information on potential interaction would be useful to assess the need for dose modification and the basis of the higher incidence of pancreatic toxicity associated with coadministration of the two drugs.

METHODS

ddI (200 mg/kg) and pentamidine (10 mg/kg) were administered by continuous infusion to rats over 3 hr, either alone or concomitantly. Drug analysis was by high pressure liquid chromatography with UV or fluorescence detection, or by radioimmunoassay.

RESULTS

Pentamidine coadministration significantly increased the apparent volume of distribution at steady state of ddI from 1.4 to 3.4 l/kg (p = 0.004), and increased the mean residence time from 36.3 to 50.0 min (p = 0.015). Pentamidine enhanced the distribution of ddI from plasma into pancreas (p = 0.001) and muscle (p = 0.026). ddI distribution into spleen and liver was also increased, with differences approaching statistical significance (p = 0.08 and 0.06, respectively). In contrast, ddI coadministration did not affect the total body clearance but increased the urinary excretion and the renal clearance of pentamidine by about 5-fold (p = 0.0003).

CONCLUSIONS

These data indicate that pentamidine increased the distribution of ddI into pancreas and muscle, whereas ddI increased the renal elimination of pentamidine.

WR-1065 and radioprotection of vascular endothelial cells. I. Cell proliferation, DNA synthesis and damage

Normal tissue toxicity limits radiation therapy and could depend on the extent of damage to the vascular endothelium Aminothiols such as WR-1065 [N-(2-mercaptoethyl)-1,3-diaminopropane] provide radioprotection for normal tissues, but little is known about how the aminothiols specifically affect the endothelium. Bovine aortic endothelial cells in culture were exposed to WR-1065 for 2 h before irradiation (137Cs gamma rays, 1 Gy/min). Alone, WR-1065 demonstrated an antiproliferative effect that was related to dose (0.5-4 mM) and was evident by lowered counts of adherent cells 48 h after exposure. WR-1065 was clearly radioprotective when assessed by colony formation and incorporation of [3H]thymidine. However, when the number of adherent cells was evaluated, radioprotection appeared to be slight and evident only in logarithmically growing cells. WR-1065 at 2 mM suppressed single-strand DNA breaks after 3 Gy by 22% and double-strand breaks after 9 Gy by 47%. Also in the irradiated cells, WR-1065 more than doubled the rate of progression of cells from G1 to S phase. WR-1065 pretreatment elevated cellular glutathione (GSH) content more than twofold. Although pretreatment with buthionine sulfoximine inhibited the elevation of GSH, the radioprotective impact of WR-1065 on total DNA strand breaks and colony formation was unaffected. These results suggest that WR-1065 may enable tissue recovery from irradiation by promoting the replication of endothelial cells, possibly by mechanisms independent of GSH.

Neurotrophin-induced modulation of synaptic transmission in the adult hippocampus

The NGF-family of neurotrophic factors including NGF, BDNF and NT-3,4/5 is known to be crucial for neuronal survival and differentiation during development. However, recent studies suggest that the neurotrophins are also widely expressed and play a dynamic role in the mature nervous system. One of the major sites of expression of the neurotrophins in the adult brain is the hippocampus which has been also popular as an important structure for the adult plasticity. Moreover, the level of expression of the neurotrophins in the hippocampus can be regulated by a variety of neuronal inputs, such as experimentally-induced seizures, injection of glutamate receptor agonists, and LTP-inducing stimulation. The possibility that the neurotrophins modulate synaptic transmission in the mature brain has been investigated at the Schaffer collateral-CA1 synapses in the adult rat hippocampus. We report that transient application of BDNF and NT-3, but not NGF induces a long-lasting increase of synaptic transmission, which is likely to be mediated by Trk family of receptor tyrosine kinases. Both BDNF and NT-3 decrease paired pulse facilitation, suggesting a possible presynaptic modification. Interestingly, previous potentiation of synaptic activity by the application of neurotrophic factors does not occlude the induction of long-term potentiation. These results suggest that the neurotrophins may locally regulate synaptic plasticity in the adult nervous system.

Tissue pharmacokinetics of 2',3'-dideoxyinosine in rats

The present study examined in rats the concentration-time profiles of 2',3'-dideoxyinosine (ddI) in pharmacologically relevant tissues, including organs where drug effects are desired (brain, lymph nodes, spleen), organs with known drug toxicity (pancreas), and major eliminating organs (liver, kidney). ddI was analyzed by high performance liquid chromatography and radioimmunoassay. In the liver, pancreas, spleen, brain and lymph nodes, the highest concentrations were reached between 4 and 7 min after drug administration. The concentrations subsequently declined in parallel with those in plasma, indicating that plasma and these tissues were in rapid equilibrium. The concentrations in these tissues were less or equal to that of plasma. In the kidney, the maximal concentration occurred at a later time of 14 min, after which concentrations also declined in parallel to those in plasma. The kidney concentrations were about 10-fold greater than plasma concentrations. The ratios of tissue-to-plasma concentrations and of areas under the tissue and plasma concentration-time profiles showed a 230- to 300-fold range with the rank order of kidney >> liver approximately pancreas > lymph nodes > spleen >> brain, with respective values of 10.4, 1.09, 0.90, 0.75, 0.42, and 0.04. These data indicate no accumulation of ddI in brain, lymph nodes, spleen, pancreas and liver, and a significant accumulation in the kidney. The low tissue-to-plasma ratios in brain and spleen and a moderate ratio in lymph nodes indicate that further enhancement of the therapeutic effect of ddI requires improved drug delivery and entrapment in these tissues.

Characterization of beta-glucosidase and beta-glucuronidase of alkalotolerant intestinal bacteria

The number of alkalotolerant intestinal bacteria was 1% of the total flora in humans and 0.8% of those in rats. The beta-glucosidase and beta-glucuronidase activity of these intestinal bacteria was induced by elevating the pH of the medium, but the growth was not changed. The enzyme activity in a medium of pH 7 was 5- to 10-fold higher than that in a medium of pH 6. Isolated bacteria from human and rat feces were cultured in a pH 5 general anaerobic medium (GAM) broth to reach a stationary phase, then the pH of the media was changed from 5 to 8. Both beta-glucosidase and beta-glucuronidase were increased 9.2-12.1-fold. The activity of these enzymes was also increased 2-16-fold by adding substrates (p-nitrophenyl-beta-D-glucuropyranoside or p-nitrophenyl-beta-D-glucuronide). beta-Glucuronidase(s) was inhibited by saccharic acid 1,4-lactone or D-glucuronic acid. However, when lactulose was added to the medium, and then intestinal microflora were inoculated in the medium, the productivity of these enzymes dramatically decreased. We thus contend that the induction of the beta-glucosidase and beta-glucuronidase of intestinal bacteria by a high pH can cause colorectal cancer.

Natural occurrence of Fusarium mycotoxins (trichothecenes and zearalenone) in barley and corn in Korea

Barley is produced in four provinces, Chonbuk, Chonnam, Kyungbuk, and Kyungnam, and corn is mainly produced in the Kangwon province in Korea. The natural occurrence of Fusarium mycotoxins was surveyed in 39 barley and 46 corn samples from different areas. Five 8-ketotrichothecenes, namely deoxynivalenol (DON), nivalenol (NIV), 4-acetylnivalenol (4-ANIV), 3-acetyldeoxynivalenol (3-ADON), and 4,15-diacetylnivalenol (4,15-DANIV), and zearalenone (ZEA) were detected in barley. DON, NIV, and ZEA were the major contaminants in barley, with mean levels of 170, 1,011, and 287 ng/g, respectively. On the other hand, DON, 15-acetyldeoxynivalenol (15-ADON), NIV, 4-ANIV, 4,15-DANIV, and ZEA were detected in corn samples. DON and 15-ADON were the major contaminants in corn, with mean levels of 310 and 297 ng/g, respectively. The survey indicated that the natural occurrence of monoacetyl-DON and the ratios of NIV to DON in two cereals were different. In addition, this is the first report of the natural occurrence of 4,15-DANIV in cereals.

Transient spontaneous remission in acute promyelocytic leukemia--two case reports

Two cases of spontaneous remission in acute promyelocytic leukemia are reported. They had precedent febrile episodes and subsequent resolution of all clinical and hematological abnormalities occurred after supportive care including administration of various antibiotics. Their remissions lasted for 12 and five months respectively, when they relapsed.

Acute leukemias with unusual immunophenotypes

Over a two-year period, immunophenotypic patterns of 266 acute leukemia cases were analyzed using a panel of tests including TdT, SmIg and 9 surface antigens by the immunofluorescence stains for the assessment of the incidence and grade of phenotypic ambiguity (lineage infidelity) and the possible clinical significance of unusual immunophenotypes. Immunophenotypes were classified into four groups according to the degree of ectopic antigen expression. We classified as Group A (91.7%, 244 of 266 cases) those expressing conventional pattern without ectopic antigen. Group B (3.0%, 8 of 266 cases) was defined to have at least two lineage specific markers and single ectopic antigen. Such a "low grade deviation" did not prevent a definite immunodiagnosis. Group C (4.2%, 11 of 266 cases) revealed a promiscuous coexpression of markers related to different lineages, including two cases (0.8%, 2 cases) of biphenotypic leukemia. Group D (1.1%, 3 cases) included unclassifiable immunophenotypes with no antigen or HLA-DR only expression. Both patients with biphenotypic leukemia and one patient with unclassifiable immunophenotypes failed to respond to induction chemotherapy, suggesting a poor prognosis in these patients. The incidence of acute myelogenous leukemia (AML) cases with one or more ectopic surface antigens was 10 (8.1%) of the 124 AML cases. Ectopic antigen expression was seen in 5 (4%) of the 125 B-lineage acute lymphoblastic leukemia (ALL) cases and 3 (25%) of the 12 T-ALL cases. It is concluded that nearly 95% of cases of acute leukemia cases can be diagnosed accurately with immunophenotyping alone including patients with a mild degree of deviation from expected antigenic patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

pH-inducible beta-glucosidase and beta-glucuronidase of intestinal bacteria

beta-Glucosidase and beta-glucuronidase of human and rat fecal bacteria were induced by cultivation in alkaline media although their growths were not affected. When a bacterium isolated from human feces producing each enzyme was cultured in a medium at pH 5 for 12-15 h and then adjusted to pH 8, beta-glucosidase and beta-glucuronidase were induced 9.2-fold and 11.5-fold, respectively.

Blood gas and electrolyte changes after tourniquet application in total knee replacement surgery

The tourniquet is widely used in upper and lower extremity surgery in orthopedic practice. However, safe working guidelines for the application of the tourniquet are not clearly defined. The use of a tourniquet is an important step in performing total knee arthroplasty, and it seems plausible that mechanical damage is directly related to the height and the duration of the pressure of the tourniquet applied. Even the tourniquet pressure which is widely accepted in clinical practice, if it is applied for several hours, would permanently damage not only tissues directly under the tourniquet but also the muscles and the nerves distal to the tourniquet. The resultant ischemia to limb produces local changes including hypoxemia, acidosis and hyperkalemia. Relatively little is known about the systemic effects of tourniquet release when the patient is undergoing total knee replacement surgery under a general anesthesia. Therefore, we studied the systemic effects. The results were as follows: 1) Approximately five minutes after the tourniquet was released there was a statistically significant increase in mean heart rate.: 2) Serum potassium levels tended to increase significantly until five minutes while the serum sodium level rose significantly only one minute, and the lactate level rose significantly for only two minutes after tourniquet released; 3) PaCO2 increased for five minutes after tourniquet release and remained elevated for 30 minutes; 4) PaO2 did not change significantly two minutes after tourniquet release; 5) The mean pH dropped to 7.34 and remained low for over five minutes.

An experimental intraarticular implantation of woven carbon fiber pad into osteochondral defect of the femoral condyle in rabbit

The defects of the articular cartilage structure are not replaced unless the subchondral plate has been breached. However, following the creation of a defect in the subchondral plate, the area is filled in with a fibrous tissue which gradually transforms to hyaline cartilage. The porous nontoxic materials of both biologic and synthetic origin have reportedly been used as matrices for repairing bone and cartilage. Following implantation, carbon fibre, chemically inert and well-tolerated by the body, induces a proliferation of ordered fibrous tissue. We implanted carbon fiber pads in osteochondral defects in rabbits. Those repairs were compared to control holes with no implants. The pads appeared to induce the gross appearance of a restored joint surface, mechanically strong to loading for periods from 2 to 6 weeks. Also, carbon fiber pads promoted the healing of the osteochondral defects in the rabbit femoral condyle, supplying well-organized cartilagenous tissue over repaired subchondral bone. The use of carbon fiber pads as implant material is suggested for the restoration of articular surface in osteoarthritis and osteochondritis dissecans.

An experimental study of healing of the partially severed flexor tendon in chickens

There is a lack of clinical and experimental studies of the treatment of incompletely transected tendons. The controversy concerning the source of flexor tendon nutrients is of important clinical concern in healing of the injured tendon; thus, the flexor tendon blood supply has cited as a reason for using specific tendon suture techniques, and as a rationale for preserving the superficialis tendon and its vincula during tendon repair surgery. Our knowledge of the normal physiology of digital flexor tendons and the mechanism of their healing process is deficient. The aim of this study was to investigate the relative importance of the synovial fluid and the blood supply respectively for the healing of partially severed flexor tendons. We observed the sequential histological and vascular changes which occur in healing of the partial lacerations in the dorsal and plantar aspects of the tendons. We observed the vascularities of the two partially severed tendon groups after injection of microfil and india ink through the femoral artery. In the healing process there was no sequential histological difference between the dorsal and the plantar severed tendons. The vascularity patterns of the healing tendons were significantly increased and the hypervascularity of dorsal severed tendons was greater than that of plantar severed tendons. Partially severed tendons were completely healed without surgical repair with dense collagen fibers without adhesion in most cases. We concluded from this study that the blood vessels appeared to play a significant role in the healing of the severed flexor tendons. An intact synovial environment did not seem to be required for healing of the severed tendon. It is not necessary to surgically repair the partially severed tendon for prevention of rupture and adhesion.

Autolysed antigen-extracted allogeneic bone for repair of diaphyseal bone defects in rabbits

Autolysed antigen-extracted allogeneic bone (AAA bone) was used to bridge a large osteoperiosteal gap in the diaphysis of the radius of 50 rabbits. Periodic observations of the graft were made clinically, radiologically and histologically every week up to fourteen weeks. The continuity of the radius was evaluated macroscopically and histologically. The AAA bones were progressively resorbed and replaced by the new bone. The bone remodelled to the mature tubular bone and did not undergo absorption during the experimental period. The AAA bone proceeded to be an osteoinductive and osteoconductive material. There were no appreciable histologic signs of immune or foreign body reaction.

The effect of experimental trypsin on the regeneration of hyaline articular cartilage

There is evidence from other studies that some degree of cartilage healing may take place after the initiation of an inflammatory response. It is postulated that the induction of the platelet-cartilage interaction may eventuate in cartilage repair. The treatment of fresh articular cartilage with proteolytic enzymes rendered the tissue active as a platelet aggregant. During platelet aggregation a host of active substances are released which are known to play a role in the inflammatory response (Thompson 1975). This study was undertaken to evaluate the effects of trypsin on the surface injury of rabbit hyaline cartilage. The results were as follows: 1) Hyaline cell regeneration was observed only in the group treated with trypsin and blood; 2) Hyaline cartilage regeneration did not occur in the group treated with a single injection of trypsin or blood; 3) There was no significant damage to the healthy articular cartilage by the single injection of trypsin or blood, or both; and 4) Platelets do not adhere to cartilage and superficial damaged cartilage does not induce platelet aggregation.

Changes in the hyaline articular cartilage after air exposure

The changes of hyaline articular cartilage from rabbits after air exposure were evaluated. The knee joints were exposed to air for periods of thirty minutes to two hours. The animals were killed periodically, at three days, one week and three weeks postoperatively. After sacrifice, the cartilage was removed and prepared for study by light microscopy and electron microscopy. Exposure to room air for thirty minutes produced chondrocyte necrosis in the upper third of the cartilage, and exposure for 60 minutes or longer produced chondrocyte necrosis of the entire thickness of articular cartilage at three days after arthrotomy. But, three weeks after arthrotomy, we could not find any chondrocyte necrosis in any rabbits at varying periods of air exposure. There was no significant change in proteoglycan content between the aired and control cartilage.

CLINICAL RELEVANCE

Exposing cartilage to air can cause transient and reversible cartilage damage. If these changes are not reversible, the orthopedic surgeon should consider avoiding the prolonged exposure of articular cartilage to air, since complete matrix disintegration is known to occur months after chondrocyte necrosis.

Pemphigus foliaceus induced by rifampicin

Pemphigus foliaceus was seen in a patient with pulmonary tuberculosis during rifampicin therapy. The skin lesions were eczematoid patches, flaccid bullae and crusted plaques on the trunk and extremities, histologically showing a high epidermal blister with acantholysis. The diagnosis was confirmed by immunofluorescent studies. After the patient discontinued rifampicin, the skin lesions cleared completely within 5 weeks without any systemic medication.